let str1 = "str";
let str2 = 'str';

// ES6可以使用反引号定义字符串
let str3 = `str`;

let human = {
    name: "宋金宇",
    age: 23,
    sex: "男"
}

let str4 = `姓名：${human.name}，年龄：${human.age}，性别：${human.sex}`;
console.log(str4);

function sum(a,b) {
    return a + b;
}

let a = 2;
let b = 3;
let str5 = `a + b = ${sum(a,b)}`;
console.log(str5);
